Lines Matching refs:PWM

1 Pulse Width Modulation (PWM) interface
3 This provides an overview about the Linux PWM interface
7 the Linux PWM API (although they could). However, PWMs are often
10 this kind of flexibility the generic PWM API exists.
15 Users of the legacy PWM API use unique IDs to refer to PWM devices.
17 Instead of referring to a PWM device via its unique ID, board setup code
18 should instead register a static mapping that can be used to match PWM
36 Legacy users can request a PWM device using pwm_request() and free it
40 device or a consumer name. pwm_put() is used to free the PWM device. Managed
43 After being requested, a PWM has to be configured using:
47 To start/stop toggling the PWM output use pwm_enable()/pwm_disable().
54 /sys/class/pwm/. Each probed PWM controller/chip will be exported as
55 pwmchipN, where N is the base of the PWM chip. Inside the directory you
58 npwm - The number of PWM channels this chip supports (read-only).
60 export - Exports a PWM channel for use with sysfs (write-only).
62 unexport - Unexports a PWM channel from sysfs (write-only).
64 The PWM channels are numbered using a per-chip index from 0 to npwm-1.
66 When a PWM channel is exported a pwmX directory will be created in the
70 period - The total period of the PWM signal (read/write).
72 	time of the PWM.
74 duty_cycle - The active time of the PWM signal (read/write).
77 polarity - Changes the polarity of the PWM signal (read/write).
78 	Writes to this property only work if the PWM chip supports changing
79 	the polarity. The polarity can only be changed if the PWM is not
82 enable - Enable/disable the PWM signal (read/write).
86 Implementing a PWM driver
92 to have multiple PWM drivers in the system. For this reason it's mandatory
93 for new drivers to use the generic PWM framework.
95 A new PWM controller/chip can be added using pwmchip_add() and removed
97 pwm_chip as argument which provides a description of the PWM chip, the
98 number of PWM devices provided by the chip and the chip-specific
99 implementation of the supported PWM operations to the framework.
101 When implementing polarity support in a PWM driver, make sure to respect the
102 signal conventions in the PWM framework. By definition, normal polarity
111 The PWM core list manipulations are protected by a mutex, so pwm_request()
113 PWM core does not enforce any locking to pwm_enable(), pwm_disable() and
120 Currently a PWM can only be configured with period_ns and duty_ns. For several